FAO Species Identification Guide for Fishery Purposes Western

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1312 Sharks
Carcharhinidae CARCHARHINIDAE
Requiem sharks
(also, ground sharks, blue sharks, sharpnose sharks)
by L.J.V. Compagno and V.H. Niem
Diagnostic characters: Small to large sharks. Trunk and precaudal tail cylindrical, not depressed and
without lateral ridges: precaudal tail much shorter than trunk. Head not expanded laterally, conical to
moderately depressed; 5 small- to medium-sized gill slits present, the last 1 to 3 over or behind pectoral-fin
origins, their upper ends not expanded onto dorsal surface of head; no gill sieves and usually no gill rakers
on internal gill slits (short dermal gill rakers present in Prionace); spiracles usually absent (but always
present in Galeocerdo); nostrils well separated from mouth, without barbels, nasoral grooves, or circumnarial
grooves; eyes on sides of head, with a well-developed nictitating lower eyelid; snout short to
moderately long, conical and slightly pointed to depressed and broadly rounded, never greatly flattened
and blade-like and without lateral teeth and barbels; mouth usually large, arched and elongated, and
extending well behind eyes; labial furrows usually present on both jaws but generally greatly reduced,
confined to mouth corners, and barely visible when mouth is closed (but Galeocerdo and Rhizoprionodon
species have well-developed labial furrows); upper labial furrows usually not reaching front of mouth
(except in Galeocerdo); teeth small to large, blade-like, with a single cusp and cusplets variably
developed; anterior teeth in upper jaw smaller than lateral teeth and not separated from them by
smaller intermediate teeth on each side. Two dorsal fins, without spines, the first dorsal fin moderately
large, high and angular or subangular, much shorter than the caudal fin, its base located over the interspace
between pectoral and pelvic-fin bases and entirely anterior to origins of pelvic fins (free rear tip of dorsal
fin may reach or extend posterior to pelvic-fin origins in Scoliodon, Negaprion, Rhizoprionodon, and
Triaenodon); second dorsal fin varying from less than 1/5 the height of the first dorsal fin to about as high
as the first (Lamiopsis and Negaprion); anal fin present, moderately large, with its origin varying from
somewhat anterior to the second dorsal-fin origin to under the first half of second dorsal-fin base; caudal
fin strongly asymmetrical, much less than 1/2 of total length, with a rippled or undulated dorsal margin,
a well-marked subterminal notch, and a short but well-defined lower lobe; vertebral axis of caudal fin
raised above body axis. Caudal peduncle not strongly depressed dorsoventrally or widely expanded
laterally with weak longitudinal keels (Prionace, Galeocerdo) or none; precaudal pits present and well
developed. Intestinal valve of scroll type. Colour: brown, grey, yellowish or bluish above, white to cream
or yellowish below, some species with prominent dark or light markings on fins; body usually without a
prominent colour pattern (except for Galeocerdo).
posterior margin
apex of 1 st dorsal fin
inner margin
nictitating membrane
nostril
internasal
width
anterior
nasal flap
labial folds
length of snout
width of
mouth
inner margin
of pectoral fin
position of interdorsal
ridge when present
rolled
unrolled
intestinal valve of scroll type
second dorsal fin
precaudal pit
free tip of
posterior lobe
subterminal
notch
dorsal view of caudal fin
example of upper and lower teeth
(blade-like, with a single cusp, often serrated)